Periodically losing Comcast 85MHz channels

Comcast Atlanta - I am periodically losing 4 HD channels, all 4 are 1t 85MHz. Is there anything peculiar about that frequency? No real idea how long this has been going on but I first noticed it last Thursday as it lost the signal on HSTRYHD(852) a few minutes in to the first episode of the new season of "Vikings" . I checked all of my HD capable TiVos and had no signal on all of them. I set up to record 2 different later showings on both the TiVo that had tried to record it initially and another TiVo on a different outlet. and both of them successfully recorded the episode.



Last night, the channels were there. Today they are gone.



There's a tech coming by between 1&3 today but I doubt if he'll be able to do anything.